Headlights Don't Pop Up

[Carl81]

The headlights on my 81 will go down pretty well, but they won't pop up at all from the switch. The hoses seem alright. Where would you start with replacement parts?

Thanks.










www.mycarframes.com

[gmjunkie]

Originally Posted by Carl81

The headlights on my 81 will go down pretty well, but they won't pop up at all from the switch. The hoses seem alright. Where would you start with replacement parts?

Thanks.










www.mycarframes.com

First I'd check and see if you have vacuum to the Actuators in the On position!!! Heres a Diagram of the headlamp vacuum system so you can check it out!!! Some of it wont be used on your car because up to 72 and Including had a vacuum Wiper Door!!

[Carl81]

Thank you.

I have had a new seal and sleeve to rebuild one of my actuators for a long time, but they are still sitting in the bag on the bench. I would guess if one leaked badly, it would keep the other from working as well or am I wrong about that?

I will of course check for vacuum first. What would be a reasonable amount of vacuum to have at each check spot?

Thanks again.








www.mycarframes.com

[gmjunkie]

Originally Posted by Carl81

Thank you.

I have had a new seal and sleeve to rebuild one of my actuators for a long time, but they are still sitting in the bag on the bench. I would guess if one leaked badly, it would keep the other from working as well or am I wrong about that?

I will of course check for vacuum first. What would be a reasonable amount of vacuum to have at each check spot?

Thanks again.








www.mycarframes.com

It would have to be a Really Bad leak!!! And then your engine would run like it had a Bad Vac leak!!! The actuators are on 2 separate vac systems controlled by one!! I think you will find that the problem is in the smaller lines or the Headlamp switch or Over ride!!

[Carl81]

Thanks.

As soon as it get back from the shop (dash electric problems), then I am going to hit the headlight problem. Maybe then I can turn on the lights in the rain without getting wet.










www.mycarframes.com

[Anti Venom]

In my experience, the first thing that I check is the vacuum reserve canister. Located in the front bumper it looks like a Coffee can. If it is leaking, you won't have enough vacuum to do much with the headlights.

[vettejack]

Buy a C6...problem solved!

[Carl81]

Thanks. I will try that. I know my canister has a nice dent in it. (Taking a few too many side trips to the neutral ground to avoid accidents and road debris.)





www.mycarframes.com

[KOPBET]

We can break it down into logical steps. Hopefully, Junkie will keep me straight here...

http://www.corvette-101.com/images/vacsys.jpg

Red closes the lights, and is the normally open side of the relay.
Green opens the lights, and is the normally closed side of the relay.
Yellow is the common source vacuum from the tank.

The relay is a normally closed (green side) vacuum switch. Vacuum applied to the metal control line changes vacuum direction to the normally open (red) side.

The line in the center with the tee is the up/down control line. Vacuum present here closes the headlights (your headlights will go down when you start the engine if they are up). Vacuum absent here opens the lights (assuming vacuum is present at the source).

Troubleshooting:

Check for correct routing of the hoses.

Pull both yellow hoses. Plug one of them. Start the engine and check for 10-15" vacuum at the other yellow hose. You can check at the vacuum tank. If you don't have any vacuum or have low vacuum check for leaks in the hoses or in the vacuum tank, or a bad check valve (gray metal, 3 connects) or a plugged vacuum filter (white plastic, 2 connects).

If vacuum is good at the yellow, jumper the yellow hose to the green hose with a smaller piece of hose or a small piece of tubing (or use a hand vacuum pump if you have one). If the headlight goes up without effort then the actuator is ok and the vacuum relay is leaking out the vacuum. If the headlight doesn't go up or goes up with difficulty then the clevis rod seal is shot or the hose is leaking (bad). You've already said the lights go down OK, so the diaphram must be good.

One side being bad will likely affect the other side operation too. Check the other side when done.


http://www.corvette-101.com/vacuum.htm

[gmjunkie]

Originally Posted by KOPBET

We can break it down into logical steps. Hopefully, Junkie will keep me straight here...

http://www.corvette-101.com/images/vacsys.jpg

Red closes the lights, and is the normally open side of the relay.
Green opens the lights, and is the normally closed side of the relay.
Yellow is the common source vacuum from the tank.

The relay is a normally closed (green side) vacuum switch. Vacuum applied to the metal control line changes vacuum direction to the normally open (red) side.

The line in the center with the tee is the up/down control line. Vacuum present here closes the headlights (your headlights will go down when you start the engine if they are up). Vacuum absent here opens the lights (assuming vacuum is present at the source).

Troubleshooting:

Check for correct routing of the hoses.

Pull both yellow hoses. Plug one of them. Start the engine and check for 10-15" vacuum at the other yellow hose. You can check at the vacuum tank. If you don't have any vacuum or have low vacuum check for leaks in the hoses or in the vacuum tank, or a bad check valve (gray metal, 3 connects) or a plugged vacuum filter (white plastic, 2 connects).

If vacuum is good at the yellow, jumper the yellow hose to the green hose with a smaller piece of hose or a small piece of tubing (or use a hand vacuum pump if you have one). If the headlight goes up without effort then the actuator is ok and the vacuum relay is leaking out the vacuum. If the headlight doesn't go up or goes up with difficulty then the clevis rod seal is shot or the hose is leaking (bad). You've already said the lights go down OK, so the diaphram must be good.

One side being bad will likely affect the other side operation too. Check the other side when done.


http://www.corvette-101.com/vacuum.htm

Damn Kop,your getting purdy well versed in C3's in the last year or so!!!